java源代码阅读

‘壹’ java阅读源码，大量英文注释阅读不方便，求集成idea里面的翻译java注释由英文翻译为中文的工具。

学会在idea（eclipse）中阅读、调试源码，是java程序员必不可少的一项技能。

在idea中配完环境后，默认其实也是能够对jdk的源码进行debug调试的。但是无法在源码中添加自己的注释，无法添加自己的理解。如果干瞪眼看的话，可能过段时间，就忘记了。下面就介绍下，如何在jdk源码中为所欲为，像在我们自己的代码中一样写注释、调代码：

打开idea，选择Project->File->Project Structure->SDKs->Sourcepath，初始状态如下图 ：

这时，再重新打开jdk的源码类，我们就可以在源java文件中，添加自己的注释了。

一定注意：添加注释时，一定不要新加一行写注释。最好在一行代码的后面，使用//进行注释。否则行号和真正的jre中编译后的代码行号对应不上，如果对源码debug时，会出现代码运行和行号不匹配的情况

‘贰’ 鎻愰珮浠ｇ爜阒呰昏兘锷涚殑鎶宸ф湁鍝浜涳纻

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‘叁’ 求用JAVA编写俄罗斯方块游戏的源代码

俄罗斯方块——java源代码提供 import java.awt.*; import java.awt.event.*; //俄罗斯方块类 public class ERS_Block extends Frame{ public static boolean isPlay=false; public static int level=1,score=0; public static TextField scoreField,levelField; public static MyTimer timer; GameCanvas gameScr; public static void main(String[] argus){ ERS_Block ers = new ERS_Block("俄罗斯方块游戏 V1.0 Author:Vincent"); WindowListener win_listener = new WinListener(); ers.addWindowListener(win_listener); } //俄罗斯方块类的构造方法 ERS_Block(String title){ super(title); setSize(600,480); setLayout(new GridLayout(1,2)); gameScr = new GameCanvas(); gameScr.addKeyListener(gameScr); timer = new MyTimer(gameScr); timer.setDaemon(true); timer.start(); timer.suspend(); add(gameScr); Panel rightScr = new Panel(); rightScr.setLayout(new GridLayout(2,1,0,30)); rightScr.setSize(120,500); add(rightScr); //右边信息窗体的布局 MyPanel infoScr = new MyPanel(); infoScr.setLayout(new GridLayout(4,1,0,5)); infoScr.setSize(120,300); rightScr.add(infoScr); //定义标签和初始值 Label scorep = new Label("分数:",Label.LEFT); Label levelp = new Label("级数:",Label.LEFT); scoreField = new TextField(8); levelField = new TextField(8); scoreField.setEditable(false); levelField.setEditable(false); infoScr.add(scorep); infoScr.add(scoreField); infoScr.add(levelp); infoScr.add(levelField); scorep.setSize(new Dimension(20,60)); scoreField.setSize(new Dimension(20,60)); levelp.setSize(new Dimension(20,60)); levelField.setSize(new Dimension(20,60)); scoreField.setText("0"); levelField.setText("1"); //右边控制按钮窗体的布局 MyPanel controlScr = new MyPanel(); controlScr.setLayout(new GridLayout(5,1,0,5)); rightScr.add(controlScr); //定义按钮play Button play_b = new Button("开始游戏"); play_b.setSize(new Dimension(50,200)); play_b.addActionListener(new Command(Command.button_play,gameScr)); //定义按钮Level UP Button level_up_b = new Button("提高级数"); level_up_b.setSize(new Dimension(50,200)); level_up_b.addActionListener(new Command(Command.button_levelup,gameScr)); //定义按钮Level Down Button level_down_b =new Button("降低级数"); level_down_b.setSize(new Dimension(50,200)); level_down_b.addActionListener(new Command(Command.button_leveldown,gameScr)); //定义按钮Level Pause Button pause_b =new Button("游戏暂停"); pause_b.setSize(new Dimension(50,200)); pause_b.addActionListener(new Command(Command.button_pause,gameScr)); //定义按钮Quit Button quit_b = new Button("退出游戏"); quit_b.setSize(new Dimension(50,200)); quit_b.addActionListener(new Command(Command.button_quit,gameScr)); controlScr.add(play_b); controlScr.add(level_up_b); controlScr.add(level_down_b); controlScr.add(pause_b); controlScr.add(quit_b); setVisible(true); gameScr.requestFocus(); } } //重写MyPanel类，使Panel的四周留空间 class MyPanel extends Panel{ public Insets getInsets(){ return new Insets(30,50,30,50); } } //游戏画布类 class GameCanvas extends Canvas implements KeyListener{ final int unitSize = 30; //小方块边长 int rowNum; //正方格的行数 int columnNum; //正方格的列数 int maxAllowRowNum; //允许有多少行未削 int blockInitRow; //新出现块的起始行坐标 int blockInitCol; //新出现块的起始列坐标 int [][] scrArr; //屏幕数组 Block b; //对方快的引用 //画布类的构造方法 GameCanvas(){ rowNum = 15; columnNum = 10; maxAllowRowNum = rowNum - 2; b = new Block(this); blockInitRow = rowNum - 1; blockInitCol = columnNum/2 - 2; scrArr = new int [32][32]; } //初始化屏幕，并将屏幕数组清零的方法 void initScr(){ for(int i=0;i<rowNum;i++) for (int j=0; j<columnNum;j++) scrArr[j]=0; b.reset(); repaint(); } //重新刷新画布方法 public void paint(Graphics g){ for(int i = 0; i < rowNum; i++) for(int j = 0; j < columnNum; j++) drawUnit(i,j,scrArr[j]); } //画方块的方法 public void drawUnit(int row,int col,int type){ scrArr[row][col] = type; Graphics g = getGraphics(); tch(type){ //表示画方快的方法 case 0: g.setColor(Color.black);break; //以背景为颜色画 case 1: g.setColor(Color.blue);break; //画正在下落的方块 case 2: g.setColor(Color.magenta);break; //画已经落下的方法 } g.fill3DRect(col*unitSize,getSize().height-(row+1)*unitSize,unitSize,unitSize,true); g.dispose(); } public Block getBlock(){ return b; //返回block实例的引用 } //返回屏幕数组中(row,col)位置的属性值 public int getScrArrXY(int row,int col){ if (row < 0 || row >= rowNum || col < 0 || col >= columnNum) return(-1); else return(scrArr[row][col]); } //返回新块的初始行坐标方法 public int getInitRow(){ return(blockInitRow); //返回新块的初始行坐标 } //返回新块的初始列坐标方法 public int getInitCol(){ return(blockInitCol); //返回新块的初始列坐标 } //满行删除方法 void deleteFullLine(){ int full_line_num = 0; int k = 0; for (int i=0;i<rowNum;i++){ boolean isfull = true; L1:for(int j=0;j<columnNum;j++) if(scrArr[j] == 0){ k++; isfull = false; break L1; } if(isfull) full_line_num++; if(k!=0 && k-1!=i && !isfull) for(int j = 0; j < columnNum; j++){ if (scrArr[j] == 0) drawUnit(k-1,j,0); else drawUnit(k-1,j,2); scrArr[k-1][j] = scrArr[j]; } } for(int i = k-1 ;i < rowNum; i++){ for(int j = 0; j < columnNum; j++){ drawUnit(i,j,0); scrArr[j]=0; } } ERS_Block.score += full_line_num; ERS_Block.scoreField.setText(""+ERS_Block.score); } //判断游戏是否结束方法 boolean isGameEnd(){ for (int col = 0 ; col <columnNum; col ++){ if(scrArr[maxAllowRowNum][col] !=0) return true; } return false; } public void keyTyped(KeyEvent e){ } public void keyReleased(KeyEvent e){ } //处理键盘输入的方法 public void keyPressed(KeyEvent e){ if(!ERS_Block.isPlay) return; tch(e.getKeyCode()){ case KeyEvent.VK_DOWN:b.fallDown();break; case KeyEvent.VK_LEFT:b.leftMove();break; case KeyEvent.VK_RIGHT:b.rightMove();break; case KeyEvent.VK_SPACE:b.leftTurn();break; } } } //处理控制类 class Command implements ActionListener{ static final int button_play = 1; //给按钮分配编号 static final int button_levelup = 2; static final int button_leveldown = 3; static final int button_quit = 4; static final int button_pause = 5; static boolean pause_resume = true; int curButton; //当前按钮 GameCanvas scr; //控制按钮类的构造方法 Command(int button,GameCanvas scr){ curButton = button; this.scr=scr; } //按钮执行方法 public void actionPerformed (ActionEvent e){ tch(curButton){ case button_play:if(!ERS_Block.isPlay){ scr.initScr(); ERS_Block.isPlay = true; ERS_Block.score = 0; ERS_Block.scoreField.setText("0"); ERS_Block.timer.resume(); } scr.requestFocus(); break; case button_levelup:if(ERS_Block.level < 10){ ERS_Block.level++; ERS_Block.levelField.setText(""+ERS_Block.level); ERS_Block.score = 0; ERS_Block.scoreField.setText(""+ERS_Block.score); } scr.requestFocus(); break; case button_leveldown:if(ERS_Block.level > 1){ ERS_Block.level--; ERS_Block.levelField.setText(""+ERS_Block.level); ERS_Block.score = 0; ERS_Block.scoreField.setText(""+ERS_Block.score); } scr.requestFocus(); break; case button_pause:if(pause_resume){ ERS_Block.timer.suspend(); pause_resume = false; }else{ ERS_Block.timer.resume(); pause_resume = true; } scr.requestFocus(); break; case button_quit:System.exit(0); } } } //方块类 class Block { static int[][] pattern = { {0x0f00,0x4444,0x0f00,0x4444},//用十六进至表示，本行表示长条四种状态 {0x04e0,0x0464,0x00e4,0x04c4}, {0x4620,0x6c00,0x4620,0x6c00}, {0x2640,0xc600,0x2640,0xc600}, {0x6220,0x1700,0x2230,0x0740}, {0x6440,0x0e20,0x44c0,0x8e00}, {0x0660,0x0660,0x0660,0x0660} }; int blockType; //块的模式号（0-6） int turnState; //块的翻转状态（0-3） int blockState; //快的下落状态 int row,col; //块在画布上的坐标 GameCanvas scr; //块类的构造方法 Block(GameCanvas scr){ this.scr = scr; blockType = (int)(Math.random() * 1000)%7; turnState = (int)(Math.random() * 1000)%4; blockState = 1; row = scr.getInitRow(); col = scr.getInitCol(); } //重新初始化块，并显示新块 public void reset(){ blockType = (int)(Math.random() * 1000)%7; turnState = (int)(Math.random() * 1000)%4; blockState = 1; row = scr.getInitRow(); col = scr.getInitCol(); dispBlock(1); } //实现“块”翻转的方法 public void leftTurn(){ if(assertValid(blockType,(turnState + 1)%4,row,col)){ dispBlock(0); turnState = (turnState + 1)%4; dispBlock(1); } } //实现“块”的左移的方法 public void leftMove(){ if(assertValid(blockType,turnState,row,col-1)){ dispBlock(0); col--; dispBlock(1); } } //实现块的右移 public void rightMove(){ if(assertValid(blockType,turnState,row,col+1)){ dispBlock(0); col++; dispBlock(1); } } //实现块落下的操作的方法 public boolean fallDown(){ if(blockState == 2) return(false); if(assertValid(blockType,turnState,row-1,col)){ dispBlock(0); row--; dispBlock(1); return(true); }else{ blockState = 2; dispBlock(2); return(false); } } //判断是否正确的方法 boolean assertValid(int t,int s,int row,int col){ int k = 0x8000; for(int i = 0; i < 4; i++){ for(int j = 0; j < 4; j++){ if((int)(pattern[t][s]&k) != 0){ int temp = scr.getScrArrXY(row-i,col+j); if (temp<0||temp==2) return false; } k = k >> 1; } } return true; } //同步显示的方法 public synchronized void dispBlock(int s){ int k = 0x8000; for (int i = 0; i < 4; i++){ for(int j = 0; j < 4; j++){ if(((int)pattern[blockType][turnState]&k) != 0){ scr.drawUnit(row-i,col+j,s); } k=k>>1; } } } } //定时线程 class MyTimer extends Thread{ GameCanvas scr; public MyTimer(GameCanvas scr){ this.scr = scr; } public void run(){ while(true){ try{ sleep((10-ERS_Block.level + 1)*100); } catch(InterruptedException e){} if(!scr.getBlock().fallDown()){ scr.deleteFullLine(); if(scr.isGameEnd()){ ERS_Block.isPlay = false; suspend(); }else scr.getBlock().reset(); } } } } class WinListener extends WindowAdapter{ public void windowClosing (WindowEvent l){ System.exit(0); } } 22